Paint画笔

public class PaintTest extends Activity{

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		setContentView(new PaintView(this));
	}
}

class PaintView extends SurfaceView implements Callback,Runnable{
	private Thread mThread;
	private Canvas mCanvas;
	private boolean mFlag;
	private Paint mPaint;
	private SurfaceHolder mSurfaceHolder;
	private Bitmap mBitmap;
	
	public PaintView(Context context) {
		super(context);
		mSurfaceHolder=this.getHolder();
		mSurfaceHolder.addCallback(this);
		mPaint=new Paint();
		mPaint.setColor(Color.WHITE);
		mPaint.setAntiAlias(true);
		mBitmap=BitmapFactory.decodeResource(getResources(), R.drawable.image);
	}

	@Override
	public void surfaceChanged(SurfaceHolder holder, int format, int width,
			int height) {
		// TODO Auto-generated method stub
		
	}  

	@Override
	public void surfaceCreated(SurfaceHolder holder) {
		mFlag=true;
		mThread=new Thread(this,"My Thread");
		mThread.start();
	}

	@Override
	public void surfaceDestroyed(SurfaceHolder holder) {
		mFlag=false;
	}

	@Override
	public void run() {
		while (mFlag) {
			long start=System.currentTimeMillis();
			myDraw();
			logic();
			long end=System.currentTimeMillis();
			if ((end-start)<50) {
				try {
					Thread.sleep(50-(end-start));
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}

	private void logic() {
		// TODO Auto-generated method stub
		
	}

	private void myDraw() {
		try {
			mCanvas=mSurfaceHolder.lockCanvas();
			if (mCanvas != null) {
				mCanvas.drawColor(Color.WHITE);
				//Set brush no teeth
				Paint paint=new Paint();
				mCanvas.drawCircle(40, 30, 20, paint);
				paint.setAntiAlias(true);
				mCanvas.drawCircle(100, 30, 20, paint);
				
				//Set the transparency of the brush
				mCanvas.drawText("No Transparency", 130, 70, paint);
				Paint paint2=new Paint();
				paint2.setAlpha(0x77);
				mCanvas.drawText("Semi-transparency", 20, 70, paint2);
				
				//Set anchor to draw text
				mCanvas.drawText("Anchor", 20, 90, new Paint());
				Paint paint3=new Paint();
				paint3.setTextAlign(Paint.Align.CENTER);
				mCanvas.drawText("Anchor", 20, 105, paint3);
				
				//Get text width
				Paint paint4=new Paint();
				float len=paint4.measureText("TextWidth");
				mCanvas.drawText("TextWidth:"+len, 20, 130, paint4);
				
				//Set paint style
				mCanvas.drawRect(20, 140, 40, 160, new Paint());
				Paint paint5=new Paint();
				paint5.setStyle(Paint.Style.STROKE);//Set the brush does not fill
				mCanvas.drawRect(60, 140, 80, 160, paint5);
				
				//Set paint color
				Paint paint6=new Paint();
				paint6.setColor(Color.GRAY);
				mCanvas.drawText("Gray", 20, 180, paint6);
				
				//Set brush thickness
				mCanvas.drawLine(20, 200, 70, 200, new Paint());
				Paint paint7=new Paint();
				paint7.setStrokeWidth(7);
				mCanvas.drawLine(20, 220, 70, 220, paint7);
				
				//Set text size
				Paint paint8=new Paint();
				paint8.setTextSize(20);
				mCanvas.drawText("TextSize", 20, 260, paint8);
				
				//Set the brush ARGB component
				Paint paint9=new Paint();
				paint9.setARGB(0x77, 0xff, 0x00, 0x00);
				mCanvas.drawText("Translucent red", 20, 280, paint9);
				
			}
		} catch (Exception e) {
			// TODO: handle exception
		}finally{
			if (mCanvas != null) {
				mSurfaceHolder.unlockCanvasAndPost(mCanvas);
			}
		}
	}
	
}

问题一：

paint9.setARGB(0x77, 0xff, 0x00, 0x00); 

这是按照16进制换算的，ff表示最大，77表示一半，这个合起来表示:红色半透明 Translucent red